When regulating travel dynamics it is advantageous if the system is informed whether the vehicle is travelling straight-on or is cornering. It is also important to have this information in the case of ABS systems e.g. when the braking force distribution is to be regulated. However the information can also be used for automatic slip control systems to optimize regulation.
A signal of this type indicating that a vehicle is travelling straight-on can be obtained in a simple manner as a result of the sums of the rotational speed signals of the wheels on the sides of the vehicle being compared with one another. As long as the difference VXU does not exceed a vehicle-dependent threshold it is detected that the vehicle is travelling straight-on.
In U.S. Pat. No. 5,415,469, incorporated herein by reference, the difference VXU is filtered to produce VXG, which is then compared to the threshold value. When VXG exceeds the threshold, travel in a curve is indicated, and an increase in brake pressure at the rear wheels is prevented.
In U.S. Pat. No. 5,313,922, incorporated herein by reference, a signal indicating travel in a straight line or a curve is used to influence the fuel supply to the engine. When travel in a curve is indicated, the braking force exerted by the engine on the driven wheels may be reduced.
U.S. Pat. No. 5,124,921 discloses a method for determining travel in a curve, wherein the curve detection signal can be used to shut down the delay of yaw speed build-up in an ABS.